1. Field of the Invention
This invention is related in general to the field of automated data storage systems for storing and retrieving data storage devices, particularly methods for reading volume identification and identifying contents of removable hard disk drives or other removable drives of a library without powering up each removable hard disk drive or other removable drive.
2. Discussion of the Background
Data storage libraries are available for data processing systems wherein a plurality of tape cartridges are stored in respective cells so that they are accessible by a robot, or “picker”, which accepts a cartridge from an input-output port and inserts it into a cell or tape drive, transfers tape cartridges between cells and a tape drive, or places a cartridge into the input-output port for retrieval. However, tape cartridges are subject to wear and access speed limitations.
Another medium that might be used in a data storage library instead of a tape cartridge is a removable hard disk drive. However, such disc drives are subject to catastrophic failure such as: (1) inability to power up the device; (2) loss or corruption of partition information; (3) loss or corruption of directory structure; or (4) loss or corruption of data.
If a hard drive can no longer be powered up then access to data on the hard drive requires an inconvenient and time consuming process of physically repairing the device during which time additional corruption may occur to the partition table, directory structure, or data. If the partition table is corrupted, then the partition information can only be reconstructed using heroic efforts, if at all. If the directory structure or data is lost or corrupted, they may be recovered, but only if imaging information about the drive can be obtained. In most applications, imaging information is collected by software programs and stored on the hard drive itself. If the hard drive has suffered a catastrophic failure that prevents it from being powered up or has resulted in a loss of the partition table, then the image information can not be obtained and the directory structure or data cannot be recovered.
One method of recovering data after a catastrophic hard disk drive failure is to use a redundant array of independent disks (“RAID”). RAID is a way of storing a set of data and parity information on multiple hard disk drives, which increases fault tolerance. Using a RAID 3,4, or 5 system with parity or a RAID 1 system with simple mirroring allows for reconstruction of lost data due to a catastrophic hard disk drive failure.
Therefore, in order to create and maintain removable hard disk drive inventory tables without introducing additional wear and increasing the likelihood of failure to the drive, it would be desirable to obtain VOLID, partition information, directory structure or other information from a removable hard disk drive without powering it up.
It would also be desirable to have access to VOLID, partition information, directory structure or other information about a removable hard disk drive that is available even if the drive has suffered a catastrophic failure, so that a recovery and rebuild activity can occur.
It would further be desirable to store VOLID, partition information, directory structure information or other information about a removable hard disk drive on a memory device which cannot be separated from its respective removable hard disk drive during normal use.
Fry, et al. U.S. Pat. No. 6,172,833 describes a data storage system for use with a tape cartridge having a tape media for storing data in a serpentine pattern, the tape cartridge having a memory device for storing a device block map for said tape media. Fry discloses the use of a memory device to store a device block map of a tape cartridge that provides information that allows for optimal retrieval of serpentine pattern data from the tape media. The device block map for the tape cartridge is analogous to the directory structure of a hard disk drive. However, Fry describes accessing the memory device to obtain the block map in conjunction with reading data from or writing data to the tape cartridge. The memory device is not used for VOLID purposes, nor is the block map stored in the memory device used to recover or rebuild a corrupted tape cartridge.
Wyde, et al. U.S. Pat. No. 6,138,222 describes a computer system specifically comprising a non-removable disk drive that has a storage capacity that may exceed 7.875 Gigabytes of information and further comprising a non-volatile memory device that includes firmware that is executed during system initialization. The firmware in the memory device is only active when the hard disk drive is powered up and acts as an interpreter, converting cylinder and head information reported by the hard drive into hard drive capacity information that is then reported to the operating system of the computer.
Lin, et al. U.S. Pat. No. 5,721,952 describes a technique for a computer system to automatically detect the type of hard disk drive installed in the system. This method includes retrieving data from a partition table and calculating the necessary parameters from the values in the partition table, specifically, calculating a HEAD parameter and a SECTORS/TRACK parameter from certain addresses stored in the partition table. The partition table indicated is an integral component of the hard disk drive.
Leyda U.S. Pat. No. 5,794,032 describes a system for the automatic identification and configuration of a computer peripheral using an initialization program to send one or more query instructions to a peripheral device such as a CD-ROM drive. In response to the query instructions, the CD-ROM drive replies with data that can be used to identify the model number or type of CD-ROM drive. The system described by Leyda requires the drive to be powered up before it will respond to a query command.
Pruett et al, U.S. Pat. No. 6,154,790 describes a method and system for retrieving and reporting serial numbers of hard disk drives in a computer system. The invention includes copying the serial number of each of the hard disk drives to a radio frequency (“RF”) enabled memory. The serial numbers can be logged utilizing a RF reader. This device provides wireless electronic tracking of computer assets such as hard disk drives, but does not teach reporting the serial numbers of disk drives, or making partition information, directory structure or other information from the hard drive available so that it may be used to recover or rebuild data stored on the hard drive.
It is known in the art that hard disk drive information such as VOLID, partition table information or directory structure may be stored on other memory devices such as a separate hard disk drive or removable storage media such as floppy disks or CD-ROMS to aid in the recovery/rebuild process. However, this information resides in a discrete volume of space that is not occupied by the removable hard disk drive with which it is associated. Without the physical attachment of the memory device to the removable hard disk drive, it cannot provide information that is unequivocally related to the hard disk drive.
Accordingly, if removable data storage devices such as hard disk drives, are to be used as storage media in a data storage library instead of tape cartridges, there is a need for an improved method and apparatus for maintaining VOLID, RAID information, partition table information, directory structure information and other information about the removable data storage devices. Further, there is a need for such a method and apparatus that does not rely on the viability of the removable drive and does not require the removable drive to be powered up. In particular, there has been a need for a memory device that is physically associated with a removable drive, occupies the same volume of space as the removable drive, and cannot be separated from the removable drive during normal use.